An image forming apparatus capable of collective printing, including a display part that displays information, a setter having a function for setting collective printing, and a controller that controls information displayed in the display part on the basis of an item set by the setter, is known as an example of a conventional technique (see Patent Document 1, for example).
The setter of this image forming apparatus has a function for setting an image magnification through a pinch-in operation. The controller has a function for designating a number of images to collect onto a single page in accordance with the image magnification set through the pinch-in operation.